Dyeing articles made of



Patented Dec. 23, 1952 DYEING ARTICLES MADE OF ACRYLONITRILE POLYMERS Jean Rampin, Ecully, France, assignor to Societe Rhodiaceta, Paris, France No Drawing. Application February 20, 1951, Serial No. 211,985. In France November 6, 1950 3 Claims.

This invention relates to a process for dyeing articles made of acrylonitrile polymers and has particular relation to a process for dyeing such polymers by coupling in situ of diazotized bases on developers.

The main object of the present invention is to provide a new and improved process, in which dyeing of polyacrylonitrile materials is carried out by subsequent treatments in two baths.

Another object of my invention is to provide a process of the before mentioned type in which the polyacrylonitrile articles can be dyed without previously subjecting said articles to swelling.

Other objects and the advantages of the invention will be apparent from the appended claims and the following specification which describes, by way of example, some embodiments of the invention.

t has been known that colorations obtained on fibers in situ by coupling diazotized bases on developers, such as particularly naphthols and their derivatives, are of very considerable technical interest in view of their excellent properties. According to the present state of the art, the obtaining of such colorations on articles made of acrylonitrile polymers, requires the application of three successive baths, 1. e. a first bath containing the naphthol or its derivative, a second bath containing an acid and a third bath containing the diazotized base. Moreover, it, has been known that even in the use of the beforementioned procedure, in order to obtain satisfactory results, it is practically necessary to use the threads in a condition of strong swelling or even jellification.

It has now been unexpectedly found that colorations of the above mentioned type can be obtained on articles and particularly on textile articles made of acrylonitrile polymers, without the necessity of subjecting them to previous swelling, by treating them in two baths only. This result is obtained according to my present invention, by treating said articles in a first bath containing the developer and the non-diazotized base and subsequently in a second bath containing nitrous acid.

I have found that in carrying out the process of my invention fixation of the non-diazotized base and developer in the first bath takes place surprisingly at temperatures, which could not be expected or inferred from the known state of art. It has been found that the temperature of this first bath should be higher than 80 0., i. e. higher than the temperature used in the hitherto known processes for dyeing with naphthols and diazotable bases, and without the necessity of exceeding the temperature of 100 C., which has been hitherto considered necessary, in a general Way, for dyeing, with a sufiicient intensity, nonswollen articles made of acrylonitrile polymers. (See particularly R. J. Thomas and P. L. Meunier,

American Dyestuif Reporter, 12/12/49, pp. 925

and 17.)

It is remarkable, that, as shown by the following examples, in the use of identical products and identical concentrations, the process of the present invention yields, even on non-swollen threads, intense colorations, while in the known procedure of three baths, on non-swollen threads either no coloration or only a very weak coloration is obtained, even if the temperature of the first of said three baths, is raised up to boiling temperature.

In carrying out the present invention, all products known for producing the dyes, i. e. all diazotable bases can be used. As developers, all products utilizable in this connection may be applied, particularly the naphthols and their derivatives, such as beta-oxynaphthoic acid and its arylides, pyrazolone derivatives, etc.

The base and the developer should be carefully dispersed in the bath. I prefer to use the base in free condition, and, in the case of a naphthol or its derivatives, to utilize it in the form of a compound with alkali. Any dispersing agent or other protecting agent can be introduced into the bath and dyeing can be carried out, according to the circumstances, in slightly acid, neutral or alkaline medium.

The second bath containing the nitrous acid may have any desired temperature, but the use of temperatures of 40 to 70 C. is particularly favorable. The bath of nitrous acid may be prepared in any desired manner, for example by dissolving sodium nitrite and adding of a mineral acid or organic acid prior to, or after, heating.

Between the first and second bath, the textile articles treated can be subjected to any useful rinsing and expressing, for example for increasing stability of the colorations to rubbing.

The following examples describe some embodiments of the invention, to which the invention is not limited.

Example 1 3 kg. of beta-naphthol and 2.25 kg. orthoamino-azo-toluene are carefully mixed to a paste with a sulfonated amino-alcohol amide. 2.1 liters of a solution of caustic soda, of 36 Be. are added. The mixture is heated to 60 under stir- 2 kgs. of sodium nitrite; 5 liters of sulfuric acid of 66 B., and 0.2 kg. of an alkyl naphthalene sulfonate.

The thread is dyed dark rose of excellent stability.

If the same thread, not subjected to previous swelling, is treated according to the known threebaths-process, even at higher concentrations of naphthol and the base, no coloration is obtained. Even if the temperature of the first bath is raised to boiling, no coloration of the previously nonswollen thread is obtained in the known procedure involving the use of three baths.

Example 2 The procedure is substantially the same as in Example 1, but the first bath contains:

4 kgs. of alpha-naphthalide of 2,3-oxynaphthoic acid;

4 kgs. of para-nitro-orthoanisidine, and

2.6 liters of caustic soda solution of 36 B.

After the treatment in the second bath, a beautiful yellow-orange coloration is obtained.

Example 3 The procedure is the same as in Example 1, but the following ingredients are charged to the first bath:

3 kgs. of beta-naphthol, 1.4 kgs. of para-nitraniline, 2.1 liters of caustic soda solution of 36 B.

A beautiful orange coloration is obtained.

Example 4 The same procedure as in Example 1 is followed, charging the following ingredients to the first bath:

4 kgs. of beta-naphthol, 4 kgs. of alpha-naphthylamine, 2.8 liters of caustic soda solution of 36 B.

An intense brown coloration is obtained.

All of the colorations thus obtained show an excellent general stability.

It will be understood that the present invention is not limited to the specific materials, steps; conditions and other specific details described above and may be carried out with various modifications without departing from the scope of the: invention as defined in the appended claims.

The term polymers of acrylonitrile or acryl-' onitrile polymers is used in the present specification and claims to include not only the poly-- acrylonitrile proper, but also co-polymers and interpolymers of acrylonitrile with other polymerizable substances, for example vinyl halides, vinylidene halides, vinyl esters and ethers, acrylic and methacrylic acids and their derivatives, particularly their amides, styrene, vinylimidazole, and others.

The polymers, co-polymers and inter-polymers used in carrying out my invention are prepared according to conventional methods, for example by polymerization of the dissolved or emulsified monomeric materials in the presence of a catalyst. I prefer the use of polymers, co-polymers and interpolymers, in which at least about 85% of the polymer is acrylonitrile and the molecular weight of which is in the range of 15,000- 250,000 or higher.

What is claimed is:

1. A process for dyeing filaments, threads and other articles of acrylonitrile polymers containing at least 85% of acrylonitrile in the molecule, by coupling in situ diazotized bases on developers, in which said articles are subjected to subsequent treatments in two baths, the first of which contains a developer and a non-diazotized base free of sulfonic groups, and has a temperature of 80-100 C., while the second bath contains nitrous acid.

2. A process as claimed in claim 1, in which the articles are subjected to rinsing between the treatments in the first and second bath.

3. A process as claimed in claim 1, in which the articles to be 'dyed are subjected to dyeing in non-swollen condition.

JEAN RAMPIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Murphy Feb. 27, 1940 OTHER REFERENCES Number 

1. A PROCESS FOR DYEING FILAMENTS, THREADS AND OTHER ARTICLES OF ACRYLONITRILE POLYMERS CONTAINING AT LEAST 85% OF ACRYLONITRILE IN THE MOLECULE, BY COUPLING IN SITU DIAZOTIZED BASES ON DEVELOPERS, IN WHICH SAID ARTICLES ARE SUBJECTED TO SUBSEQUENT TREATMENTS IN TWO BATHS, THE FIRST OF WHICH CONTAINS A DEVELOPER AND A NON-DIAZOTIZED BASE FREE OF SULFONIC GROUPS, AND HAS A TEMPERATURE OF 80*-100* C., WHILE THE SECOND BATH CONTAINS NITROUS ACID. 